Differential Diagnosis for a 6-year-old Female with Fever, Malaise, Erythematous Lesions, Gingivitis, and Mucosal Lesions

• Single Most Likely Diagnosis
  • Kawasaki Disease: This condition is characterized by fever, rash, mucous membrane changes (such as gingivitis and mucosal lesions), and changes in the extremities, which aligns closely with the symptoms described. The age of the patient also fits within the typical demographic for Kawasaki disease.
• Other Likely Diagnoses
  • Infectious Mononucleosis (Mono): Caused by Epstein-Barr virus, it can present with fever, malaise, and mucosal lesions, although the rash and specific extremity changes might be less typical.
  • Streptococcal Infection: Certain streptococcal infections, like Scarlet Fever, can cause fever, rash, and mucosal changes, including gingivitis.
  • Juvenile Idiopathic Arthritis (JIA): Some forms of JIA can present with fever, rash, and mucosal lesions, although the pattern of joint involvement would be a key distinguishing feature.
• Do Not Miss Diagnoses
  • Meningococcemia: Although less likely, this condition can present with fever, rash, and mucosal lesions. It is critical to consider due to its high mortality rate if not promptly treated.
  • Toxic Shock Syndrome: This is a life-threatening condition that can cause fever, rash, and mucosal changes. Early recognition is crucial for effective management.
  • Leptospirosis: In endemic areas, leptospirosis can cause a wide range of symptoms including fever, rash, and mucosal lesions, and is important not to miss due to its potential severity.
• Rare Diagnoses
  • Erythema Multiforme: A skin condition characterized by target lesions, which can sometimes be accompanied by mucosal lesions and fever. It's less likely but should be considered in the differential.
  • Behçet's Disease: A rare condition that can cause mucosal lesions, fever, and other systemic symptoms. It's more common in older children and adults but should be considered in the differential for recurrent or severe symptoms.
  • Systemic Lupus Erythematosus (SLE): Although rare in children, SLE can cause a wide range of symptoms including fever, rash, and mucosal lesions, and should be considered in cases where other diagnoses are ruled out.